1. Leonid Kuzmin and Ian Agulo
Through the thorns to the stars!
Igenom törnen mot stjärnorna!
Через тернии к звездам!
Chalmers University of Technology
Bolometer Group
P5. Cold-Electron Bolometer Array (CEB Array) made by E-Beam Lithography and a Shadow Evaporation Technology
Leonid Kuzmin and Ian Agulo
FKA190

2. Leonid Kuzmin, Philip Mauskopf *, and
Chalmers University of Technology
Bolometer Group
Superconducting Cold-Electron Bolometer with JFET readout for OLIMPO balloon telescope
Leonid Kuzmin, Philip Mauskopf *, and
Dmitry Golubev**
*Cardiff University, UK
**Karlsruhe Forschungszentrum, Germany
EUCAS -2005

3. OLIMPO Cardiff CLOVER + others Oxford CLOVER Phase Switch Oxford,
3-layer
technology
JFET
Voltage-
biased
SCEB
OLIMPO
Cardiff
2-layer Al-Ti
Direct Write
technology
CEB-
Series
array
JFET
Current
-biased
2-layer Ti-Al
Direct Write
technology
CEB
CLOVER
+ others
Oxford
SQUID
Shadow
Evaporation
Technology
CEB-
Parallel
array
CLOVER
Phase Switch
Oxford,
Cardiff
NbN Nanostrip
+ Finline

4. Balloon telescope OLIMPO (follower of BOOMERanG)
a multi-wavelength survey of galaxy clusters and the cosmic submm/mm background
2.6 meter antenna
A few arcmin resolution survey of the sky
150, , 600 GHz (Background load Po = pW
Background limited bolometers (2*10-17 – 1*10-16 W/Hz1/2),
64 bolom. per channel
Bolometers: TES+SQUID readout
SiN+JFET readout
CEB+JFET (or SQUID) readout
Rome Un., Cardiff Un., IROE-CNR (Italy), Caltech (USA), Santa Barbara Un. , DAFNIA/SPP (France), Tel Aviv Un., VTT (finland), Chalmers Univ.

5. Balloon telescope OLIMPO
1. Channel I: ”2.1 mm” (140 GHz)
Power load is relatively high: P0 = 2 – 3 pW
Photon noise:
Total NEP of CEB should be less than photon noise: NEPtot < NEPphot.
Single CEB doesn’t give proper results.
Only SCEB could give the proper NEP.

6. Cold-Electron Bolometer (CEB) with Capacitive Coupling to the Antenna
Cold-Electron Bolometer (CEB) with Capacitive Coupling to the Antenna Kuzmin – ISSTT-98

8. Readout Systems for CEB current measurements
SQUID with a bulk input transformer
- most sensitive
- very complicated
Chalmers Un.,
IREE, IZMIRAN, MSU,
VTT (Finland) 4K
- sensitive current measurements
- but high voltage noise
- promising with S-I-S’-I-S bolometers
Cardiff Un,
IREE, Rome Un.
4K with resonance circuits
- good for multiplexing
- need modulation technique
IPHT (Jena),
CESR (Toulouse)

9. CEB with JFET

10. Cold-Electron Bolometer Noise

11. JFET amplifier noise
We need matching with

12. Capacitively Coupled Superconducting Cold-Electron Bolometer (SCEB)
L. Kuzmin, Microelectronic Engineering, 69 (2003)

13. SCEB with JFET Total NEP is less than NEPphot for SCEB,
total iJFET=10 fA/Hz1/2,
R=0.5 kOhm and 0.1 kOhm (one junction),
Vol=0.05um3,
power load – 2 pW.
IV curves are shown for estimation of high dynamic resistance of the junctions.

14. Series Array of CEBs with JFET readout
Circle waveguide is coupled to 4 coplanar lines
Each Coplanar line is coupled to 2 CEBs

15. CEB, Current-biased, Array - 10 junctions
Total NEP is less than NEPphot
vJFET=2nV/Hz1/2 R=0.5 kOhm (one junction),
Vol=0.02um3,
power load=2 pW The power is split between bolometers and responsivity is considerably improved.

16. Total NEP of CEB and NEPphot for series array CEBs in dependence on number of CEBs
a) 600 GHz, power load P0 = 20 pW, vJFET=3 nV/Hz1/2 R=0.5 kOhm Vol=0.05um3
Optimal number of CEBs =
b) 140 GHz, power load P0 = 2 pW, vJFET=2 nV/Hz1/2 R=0.5 kOhm Vol=0.02um3.
Optimal number of CEBs = 5-10.

17. JFET in current-biased mode. Variants:
Series array of CEBs
Array of SINIS structures without biasing
Array of SN – NS Andreev contacts –thermo-voltage without biasing
Array of thermocouples (thermo-pile)
Combination of thermocouples and superconducting islands (SN Andreev contacts)
Array of CEBs – series for DC
- parallel for HF

18. Series Array of CEBs with JFET readout
Parallel for HF HF

21. Conclusions
New generation of detectors is needed to measure Cosmic Microwave Background (OLIMPO project)
Cold-Electron Bolometer (CEB) with JFET readout – very attractive option!
Single CEB with JFET – no chance!
Array of CEBs with JFET – the most attractive opportunity
SCEB (Superconducting Cold-Electron Bolometer) with JFET – realistic and effective decision